Frame Acquisition

addImageToBuffer

Adds an image to the internal buffer.

addImageToBuffer(image: DSImageData): void;

Parameters

image: an instance of DSImageData containing the image to buffer.

Return value

None.

Code Snippet

let image = cameraEnhancer.fetchImage();
cameraEnhancer.addImageToBuffer(image);

clearBuffer

Clears all images from the buffer, resetting the state for new image fetching.

clearBuffer(): void;

Parameters

None.

Return value

None.

Code Snippet

cameraEnhancer.clearBuffer()

fetchImage

Fetches the current frame from the camera’s video feed.

This method is used to obtain the latest image captured by the camera.

fetchImage(): DCEFrame;

Parameters

None.

Return value

A DCEFrame object representing the current frame. The structure and content of this object will depend on the pixel format set by setPixelFormat() and other settings.

Code Snippet

let image = cameraEnhancer.fetchImage();
document.body.appendChild(image.toCanvas());

See also

DCEFrame

getBufferOverflowProtectionMode

Retrieves the current mode for handling buffer overflow.

getBufferOverflowProtectionMode(): EnumBufferOverflowProtectionMode;

Parameters

None.

Return value

The current buffer overflow protection mode.

Code Snippet

cameraEnhancer.getBufferOverflowProtectionMode();

See also

EnumBufferOverflowProtectionMode

getColourChannelUsageType

Retrieves the current usage type for color channels in images.

getColourChannelUsageType(): EnumColourChannelUsageType;

Parameters

None.

Return value

The current color channel usage type.

Code Snippet

cameraEnhancer.getColourChannelUsageType();

See also

EnumColourChannelUsageType

getImage

Retrieves a buffered image, of type DSImageData.

This function retrieves the latest image added to the buffer, and removes it from the buffer in the process.

getImage(): DCEFrame;

Parameters

None.

Return value

A DSImageData object retrieved from the buffer which contains the image data of the frame and related information.

Code Snippet

let image = cameraEnhancer.getImage();
document.body.appendChild(image.toCanvas());

See also

DCEFrame

getImageCount

Retrieves the current number of images in the buffer.

getImageCount(): number;

Parameters

None.

Return value

The current image count in the buffer.

Code Snippet

let imageCount = cameraEnhancer.getImageCount();

getImageFetchInterval

Retrieves the current interval at which images are continuously fetched from the camera’s video feed.

getImageFetchInterval(): number;

Parameters

None.

Return value

The current fetch interval, specified in milliseconds.

Code Snippet

let fetchInterval = cameraEnhancer.getImageFetchInterval();

getMaxImageCount

Retrieves the maximum number of images that can be buffered.

getMaxImageCount(): number;

Parameters

None.

Return value

The maximum image count for the buffer.

Code Snippet

let bufferSize = cameraEnhancer.getMaxImageCount();

getPixelFormat

Retrieves the current pixel format used for images fetched from the camera.

getPixelFormat(): EnumImagePixelFormat;

Parameters

None.

Return value

The current pixel format, which could be one of the following: IPF_GRAYSCALED, IPF_ABGR_8888, and IPF_ARGB_8888.

Code Snippet

let pixelFormat = cameraEnhancer.getPixelFormat();
console.log(pixelFormat);

getScanRegion

Retrieves the current scan region set within the camera’s view.

Note: If no scan region has been explicitly set before calling this method, an error may be thrown, indicating the necessity to define a scan region beforehand.

getScanRegion(): Rect | DSRect;

Parameters

None.

Return value

A DSRect or Rect object representing the current scan region.

Code Snippet

let region = cameraEnhancer.getScanRegion();

See also

Rect

DSRect

hasImage

Checks if an image with the specified ID is present in the buffer.

hasImage(imageId: number): boolean;

Parameters

imageId: the ID of the image to check.

Return value

Boolean indicating whether the image is present in the buffer.

Code Snippet

console.log(cameraEnhancer.hasImage(10));

hasNextImageToFetch

Determines whether there are more images available to fetch.

hasNextImageToFetch(): boolean;

Parameters

None.

Return value

Boolean indicating whether more images can be fetched. false means the image source is closed or exhausted.

Code Snippet

if(!cameraEnhancer.hasNextImageToFetch()) {
    console.log("The image source is exhausted!");
}

isBufferEmpty

Determines whether the buffer is currently empty.

isBufferEmpty(): boolean;

Parameters

None.

Return value

Boolean indicating whether the buffer is empty.

Code Snippet

if(cameraEnhancer.isBufferEmpty()) {
    console.log("There is no image in buffer!");
}

setBufferOverflowProtectionMode

Sets the behavior for handling new incoming images when the buffer is full.

setBufferOverflowProtectionMode(mode:EnumBufferOverflowProtectionMode): void;

Parameters

mode: one of the modes defined in EnumBufferOverflowProtectionMode, specifying how to handle buffer overflow.

Return value

None.

Code Snippet

cameraEnhancer.setBufferOverflowProtectionMode(Dynamsoft.Core.EnumBufferOverflowProtectionMode.BOPM_UPDATE);

See also

EnumBufferOverflowProtectionMode

setColourChannelUsageType

Sets the usage type for color channels in images.

setColourChannelUsageType(type: EnumColourChannelUsageType): void;

Parameters

type: one of the types defined in EnumColourChannelUsageType, specifying how color channels should be used.

Return value

None.

Code Snippet

cameraEnhancer.setColourChannelUsageType(Dynamsoft.Core.EnumColourChannelUsageType.CCUT_FULL_CHANNEL);

See also

EnumColourChannelUsageType

setErrorListener

Sets an error listener to receive notifications about errors that occur during image source operations.

setErrorListener(listener: ImageSourceErrorListener): void;

Parameters

listener: an instance of ImageSourceErrorListener or its derived class to handle error notifications.

Return value

None.

Code Snippet

cameraEnhancer.setErrorListener(Dynamsoft.Core.EnumColourChannelUsageType.CCUT_FULL_CHANNEL);

See also

ImageSourceErrorListener

setImageFetchInterval

Sets the interval at which images are continuously fetched from the camera’s video feed.

This method allows for controlling how frequently new frames are obtained when startFetching() is invoked, which can be useful for reducing computational load or for pacing the frame processing rate.

setImageFetchInterval(interval: number): void;

Parameters

interval: the desired interval between fetches, specified in milliseconds.

Return value

None.

Code Snippet

cameraEnhancer.setImageFetchInterval(200);

setMaxImageCount

Sets the maximum number of images that can be buffered at any time.

setMaxImageCount: (count: number) void;

Parameters

count: the maximum number of images the buffer can hold.

Return value

None.

Code Snippet

cameraEnhancer.setMaxImageCount(10);

setNextImageToReturn

Sets the processing priority of a specific image so that it is returned the next time getImage() is called.

setNextImageToReturn(imageId: number, keepInBuffer?: boolean): void;

Parameters

imageId: the ID of the image to prioritize.

keepInBuffer: [Optional] boolean indicating whether to keep the image in the buffer after it has been returned.

Return value

None.

Code Snippet

cameraEnhancer.setNextImageToReturn(10);
let image = cameraEnhancer.getImage();
document.body.appendChild(image.toCanvas());

startFetching

Starts the process of fetching images.

startFetching(): void;

Parameters

None.

Return value

None.

Code Snippet

cameraEnhancer.startFetching();

setPixelFormat

Sets the pixel format for the images fetched from the camera, which determines the format of the images added to the buffer when the fetchImage() or startFetching() method is called.

setPixelFormat(pixelFormat: EnumImagePixelFormat.IPF_GRAYSCALED
                | EnumImagePixelFormat.IPF_ABGR_8888
                | EnumImagePixelFormat.IPF_ARGB_8888): void;

Parameters

pixelFormat: the desired pixel format for the images. Supported formats include IPF_GRAYSCALED, IPF_ABGR_8888, and IPF_ARGB_8888.

Return value

None.

Code Snippet

cameraEnhancer.setPixelFormat(EnumImagePixelFormat.IPF_ARGB_8888);
let image = cameraEnhancer.getImage();
document.body.appendChild(image.toCanvas());

See also

EnumImagePixelFormat

setScanRegion

Sets the scan region within the camera’s view which limits the frame acquisition to a specific area of the video feed.

Note: The region is always specified relative to the original video size, regardless of any transformations or zoom applied to the video display.

setScanRegion(region?: Rect | DSRect): void;

Parameters

region: specifies the scan region.

Return value

None.

Code Snippet

let scanRegion = {
    x: 25,
    y: 25,
    width: 50,
    height: 50,
    isMeasuredInPercentage: true
};
cameraEnhancer.setScanRegion(scanRegion); 
//...
cameraEnhancer.setScanRegion(null); //Cancel the scan region.

See also

Rect

DSRect

singleFrameMode

Controls the single-frame mode of the CameraEnhancer.

This mode is designed for scenarios where live camera feed is either not required, not supported by the browser, or when processing static images is preferred. Depending on the setting, it can alter the behavior of how images are sourced for processing.

• “disabled”: The CameraEnhancer operates in its default mode, attempting to stream live video from the camera. This is the standard behavior in environments where camera access is supported and permitted.
• “image”: The user is prompted to select a local image file for processing. This mode is useful for applications that need to process a single image instead of a continuous video stream. It can be used in any environment, regardless of camera support.
• “camera”: The behavior varies based on the device type:
  • On desktop platforms, it prompts the user to select a local image, similar to the “image” mode.
  • On mobile devices, it invokes the system camera application, allowing the user to capture a new photo for processing. This leverages the device’s camera in environments where direct camera streaming through the browser might not be available or preferred.

This property provides flexibility in handling different operational contexts, making it easier to adapt to varying application requirements and user environments.

singleFrameMode: "disabled" | "camera" | "image";

Code Snippet

(async () => {
    let cameraEnhancer = await Dynamsoft.DCE.CameraEnhancer.createInstance();
    cameraEnhancer.on('singleFrameAcquired', frameData => {
        document.body.appendChild(frameData.toCanvas());
    });
    cameraEnhancer.singleFrameMode = "image";
    await cameraEnhancer.open();
})();

As shown in the code snippet above, singleFrameMode should be set before calling open().

stopFetching

Stops the process of fetching images.

stopFetching(): void;

Parameters

None.

Return value

None.

Code Snippet

cameraEnhancer.stopFetching();

takePhoto

Initiates a sequence to capture a single frame/image, halting the video stream temporarily.

This method prompts the user to either select a local image or capture a new one using the system camera, similar to the behavior in singleFrameMode but without changing the mode.

Note: This method is intended for use cases where capturing a single, user-obtained image is necessary while the application is otherwise utilizing a live video stream.

Steps performed by takePhoto:

1. Stops the video stream and releases the camera, if it was in use.
2. Prompts the user to select an image from their gallery or disk, or to take a new image with the system camera. This behavior mirrors that of singleFrameMode.
3. Places the obtained image into the buffer, differing from singleFrameMode which would display the image in the view.
4. Attempts to resume the video stream after the image has been obtained.

takePhoto(listener: (dceFrame: DCEFrame) => void): void;

Parameter

listener: A callback function that is invoked with a DCEFrame object containing the obtained image.

Return Value

None.

Code Snippet

function handleCapturedPhoto(dceFrame) {
  console.log('Captured Photo Data:', dceFrame);
  // Process the captured photo data as needed.
}
// Capture a photo and invoke the listener with the captured data.
cameraEnhancer.takePhoto(handleCapturedPhoto);